1. Field of the Invention:
The present invention relates, in general, to fuel injection/spark ignited internal combustion engines and, more specifically, to fuel injection valves for fuel injected/spark ignited internal combustion engines.
2. Description of the Prior Art:
Fuel injection systems for internal combustion engines utilize a fuel injection valve associated with each cylinder for controlling the metering of fuel into each cylinder of the engine. The valve typically is formed of an electromagnetic coil wound about a magnetic core or stator and a spaced, movable armature core attached to a needle valve for opening and closing an injection port in the valve body. An electric current applied to the coil causes the armature to be attracted toward the stator thereby moving the needle valve to open the fuel injection port.
Such engines also employ a separate coil to provide the high voltage spark necessary to ignite the fuel in each cylinder. Such arrangements include a single coil mounted in a distributor which applies a high voltage to the individual spark plugs through contacts or points mounted in the distributor. Also, fuel ignition is achieved in a so-called "direct fire" ignition system by means of a separate coil associated with each spark plug of the engine.
Timing controls are required for energizing the fuel injection valve and igniting the spark plug of each cylinder of the engine at proper times in the engine operating cycle. In a conventional engine timing system, electronic circuits responsive to the angular rotational position of the engine crank shaft energize the coil in the fuel injection valve to control the amount of fuel metered through the valve into a particular cylinder of the engine and then energize the spark ignition coil to supply the high voltage pulse to the spark plug in the cylinder to ignite the fuel. However, the use of separate coils for the fuel injection valve and the spark ignition circuit results in a complex, space consuming system which includes numerous inherent timing problems due to the use of a large number of components.
Attempts have also been made to overcome timing problems inherent with the use of crank shaft angle based timing systems by developing valves which supply an electric spark initiate signal to the spark coil at the appropriate time in response to the buildup of fluid pressure in the fuel injection system. This eliminates the need for separate timing controls for the fuel injector valve and the spark plug; but still utilizes separate coils for the high voltage spark and the activation of the fuel injector valve.
Thus, it would be desirable to provide an improved fuel injection/spark ignition apparatus which overcomes the problems encountered with previous fuel injection/spark ignition systems. It would also be desirable to provide a fuel injection/spark ignition apparatus which uses a minimal number of components to control the metering of fuel and spark ignition. It would also be desirable to provide an improved fuel injection/spark ignition apparatus which simplifies the timing requirements for controlling both fuel injection and spark ignition.